Database reading and writing separation practice in PHP programming

With the continuous development of Internet applications, the database has become the core of data processing. In large-scale applications, the pressure of database reading and writing is huge, which will inevitably affect the performance of the entire application. In order to solve this problem, database read and write separation technology was born. This article will introduce how to achieve separation of database reading and writing in PHP programming.

1. What is database read-write separation?

Database read-write separation refers to splitting the main database and handing over the reading and writing of the main database to different nodes to improve the performance of the database. Performance and availability, reducing the read and write burden on the main database. This technology is widely used in large websites, such as e-commerce websites such as JD.com and Taobao.

Read and write separation is mainly for read and write operations under high concurrency conditions. Generally, the concurrent reads of large websites are much higher than the write operations. Therefore, write operations can be handed over to the master database, and read operations can be handed over to the slave database to achieve separation.

2. Advantages of database read-write separation

1. Improve database performance: By handing over read and write operations to different nodes for processing, operations that require system resources will be processed by different nodes respectively. Different node processing, thereby reducing node load pressure and improving database performance.

2. Improve application availability: When the primary database goes down or fails, the secondary database can automatically take over the read operations of the primary database, thereby ensuring application availability.

3. Improve the stability of the system: Database read and write separation transfers all read operations to the slave database, thereby reducing the read and write pressure on the main database and reducing the risk of system crash.

3. How to achieve read-write separation in PHP programs

There are many ways to achieve database read-write separation in PHP programs, such as using ORM framework, using database middleware, etc. The following is a simple and practical method.

1. Configuring database read-write separation

Place the write operations of the main database and the read operations of the slave database on different database nodes, which need to be added in the PHP program Configuration file, write relevant information into the configuration file. The following is a simple database configuration file:

$config'master' = 'master.host.com'; //Master library IP address
$config'master' = 'master_user'; // Main database login username
$config'master' = 'master_password'; //Master database login password
$config'master' = 'master_database'; //Main database name

$ config'slave'['hostname'] = 'slave1.host.com'; //IP address of slave 1
$config'slave'['username'] = 'slave1_user'; //Log in user from library 1 Name
$config'slave'['password'] = 'slave1_password'; //Slave database 1 login password
$config'slave'['database'] = 'slave1_database'; //Slave database 1 Name

$config'slave'['hostname'] = 'slave2.host.com'; //Slave 2 IP address
$config'slave'['username'] = 'slave2_user' ; //Login username from library 2
$config'slave'['password'] = 'slave2_password'; //Login password from library 2
$config'slave'['database'] = 'slave2_database '; //Slave database 2 database name

2. Write a connection function that separates reading and writing of the database

Connect to the master database or slave database according to different operations. The following is an example of implementing read and write separation:

//Read operation connection function
function read_db_connect()
{

global $config;
//不同的从库进行负载均衡
$count = count($config['slave']);
$rand = rand(1, $count);
$db_info = $config['slave']["$rand"];
$conn = mysqli_connect($db_info['hostname'], $db_info['username'], $db_info['password'], $db_info['database']);
return $conn;

}

//Write operation connection function
function write_db_connect()
{

global $config;
$db_info = $config['master'];
$conn = mysqli_connect($db_info['hostname'], $db_info['username'], $db_info['password'], $db_info['database']);
return $conn;

}
?>

3. Function call

When performing database operations, determine whether it is a read operation or a write operation, and just call the corresponding connection function. The following is an example:

//Query operation
function select($sql)
{

$conn = read_db_connect();
//执行查询操作
//......

}

/ /Insert operation
function insert($sql)
{

$conn = write_db_connect();
//执行插入操作
//......

}
?>

4. Precautions

1.Reading In write separation, there will be a certain delay between the master and slave databases. Therefore, after performing a write operation, you need to ensure that the data in the slave database is synchronized before performing a read operation.

2. To prevent data inconsistency from the slave database, it is recommended to synchronize data regularly.

3. When separating database reading and writing, pay attention to the database version and encoding to avoid incompatibility issues.

4. Summary

Database read and write separation improves the performance and availability of the database by separating the read and write operations of the main database, reduces the read and write burden of the main database, and thereby improves the stability of the system. In PHP programming, database reading and writing separation can be achieved through configuration files and connection functions. During the implementation process, you need to pay attention to issues such as data synchronization from the database and database version.

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